Family Ascidiidae Research Articles

Supplemental re-description of a deep-sea ascidian, Fimbrora calsubia (Ascidiacea, Enterogona), with an inference of its phylogenetic position

Fimbrora Monniot & Monniot, 1991, a macrophagous ascidian genus within the family Ascidiidae Adams & Adams, 1858, is currently monotypic, represented by F. calsubia Monniot & Monniot, 1991, a species previously recorded from the bottom of the South Pacific at depths of 1000–1860 m. The taxonomic status of Fimbrora has remained ambiguous because characteristics in its branchial papillae and neural-gland opening are incompletely known in previous studies, while these traits are essential for distinguishing other ascidiid genera. So far, no nucleotide sequence representing F. calsubia is available. In this study, we collected a single specimen of F. calsubia at a depth of 2027 m, about 400 km off the Pacific coast of Honshu, Japan. This is the deepest record, as well as the first report from the North Pacific, for the species. Our examination indicates that Fimbrora is morphologically similar to another ascidiid genus, Psammascidia Monniot, 1962, by having only secondary branchial papillae in the pharynx. Our phylogenetic analysis, based on the 18S ribosomal RNA and cytochrome c oxidase subunit I genes, along with those of 27 ascidian species available in public databases, showed that F. calsubia was more closely related to Ascidia zara Oka, 1935, Phallusia fumigata (Grube, 1864) and Phallusia mammilata (Cuvier, 1815) than to Ascidia ceratodes (Huntsman, 1912), Ascidiella aspersa (Müller, 1776) and Ascidiella scabra (Müller, 1776). Our results also indicated that acquisitions of macrophagous feeding by deep-sea members happened independently at least three times in the evolutionary history of the entire Ascidiacea.

Deep-sea ascidians from Papua New Guinea

Four deep-sea ascidian species collected during the KAVIENG 2014 expedition in Papua New Guinea are described, including additional characteristics not reported previously. Fimbrora calsubia is classified within the family Ascidiidae, Dicopia fimbriata and Octacnemus bythius within Octacnemidae, and Culeolus recumbens within Pyuridae. Anatomical observations confirmed previous descriptions for these four species collected elsewhere. Here, we describe additional morphological features for these species and provide the first barcode DNA sequences (based on a fragment of the mitochondrial gene Cytochrome Oxidase I) for D. fimbriata and C. recumbens.

HPTLC and IR Spectral studies of the ethanolic extract of Phallusia nigra

Ascidians, commonly called as Sea Squirts are sedentary tunicates. Phallusia nigra is a simple ascidian belonging to the family Ascidiidae found in plenty throughout the year. The ethanolic extract of Phallusia nigra was subjected to HPTLC and IR spectral analysis to determine the possible bioactive components. In HPTLC studies, gallic acid, ferulic acid, caffeic acid and flavonoids such as rutin, isoquercitrin and quercetin were found to be present. The interpretation of the spectrum showed the presence of aliphatic bromo compounds, phenol or tertiary alcohols, carbonyl compound, carboxylic acids, lipids, proteins, alkanes and aromatic compound.

Ascidiidae Herdman, 1882 (Tunicata: Ascidiacea) on the Pacific coast of Panama.

The ascidian fauna of the Pacific coast of Panama is poorly known and only recently four species in the family Ascidiidae were reported on. Ascidia is the only known genus of Ascidiidae in Pacific Panama waters. In the present research, we describe a new species, Ascidia sideralis sp. nov., and we document the new occurrence of A. cf. gemmata and A. cf. liberata (both previously known to the West Pacific), A. archaia (a cosmopolitan species elsewhere in the Pacific), A. ceratodes (previously documented in the eastern N. Pacific), and A. sydneiensis (an Atlantic species on the east coast of Panama) in Pacific Panama waters. A tabular key for the identification of Ascidiidae on the American Pacific coast complements this study.

Two newly recorded invasive alien ascidians (Chordata, Tunicata, Ascidiacea) based on morphological and molecular phylogenetic analysis in Korea

We report five alien ascidians with some distinct features that were investigated from August 2009 to October 2011 in Korea, among which Ascidiella aspersa (Müller, 1776) belonging to family Ascidiidae of order Phlebobranchia and Molgula manhattensis (De Kay, 1843) belonging to family Molgulidae of order Stolidobranchia are newly discovered invasive species. These ascidians were identified and their phylogenetic relationships were clarified through molecular analysis using about 680 bp of nuclear 18S rDNA and about 670 bp of mt-COI genes along with detailed morphological characteristics, and reported for the first time in Korea. It was discovered that A. aspersa was widespread three coastlines of Korea except Jeju Island, and M. manhattensis first found in Mokpo, Gunsan, and Incheon in June 2010 extended into Busan of Korea Strait in 2011.

The family Ascidiidae Herdman (Tunicata: Ascidiacea) in Bocas del Toro, Panama. Description of six new species

The family Ascidiidae Herdman (Tunicata: Ascidiacea) in Bocas del Toro, Panama. Description of six new species

The family Ascidiidae Herdman (Tunicata: Ascidiacea) in Bocas del Toro, Panama. Description of six new species

We have been collecting Ascidians in the Bocas del Toro region of Panama since August 2003, mostly in the mangroves but also in shallow coral reefs. Here we will describe six new species from this region (Phallusia fragilis, Ascidia bocatorensis, A. collini, A. corallicola, A. monnioti and A. panamensis), register and complement the description of an additional seven species in the family Ascidiidae (A. archaia, A. curvata, A. interrupta, A. cf. munda, A. sydneiensis, A. tenue and Phallusia nigra). We also provide a tabular identification key that also includes P. caguayensis and A. xamaycana. Most of the species are very abundant on mangrove roots.

Localization of Vanabins, Vanadium-Binding Proteins, in the Blood Cells of the Vanadium-Rich Ascidian, Ascidia sydneiensis samea

Some species of the family Ascidiidae accumulate vanadium in concentrations in excess of 350 mM, which is about 10 (7)-fold higher than the concentration of vanadium in seawater. In these species, signet ring cells with a single large vacuole in which vanadium ions are contained function as vanadium-accumulating cells. These have been termed vanadocytes. We recently isolated five vanadium-binding proteins, which we named Vanabin1, Vanabin2, Vanabin3, Vanabin4, and VanabinP, from vanadocytes of the vanadium-rich ascidian Ascidia sydneiensis samea. In this study, we analyzed localization of the Vanabins in the blood cells of A. sydneiensis samea using monoclonal antibodies and confocal microscopy. The Vanabin1 and Vanabin2 proteins were found in the cytoplasm and/or in some organelles of vanadocytes. Vanabin3 was also detected in the cytoplasm, while Vanabin4 was found exclusively in the cytoplasmic membrane.

Molecular biological approaches to the accumulation and reduction of vanadium by ascidians

About 90 years ago, Henze discovered high levels of vanadium in the blood (coelomic) cells of an ascidian collected from the Bay of Naples. His discovery attracted the interdisciplinary attention of chemists, physiologists, and biochemists. Two decades ago, we quantified the vanadium levels in several ascidian tissues definitively using neutron-activation analysis and revealed that some species in the family Ascidiidae accumulate vanadium at concentrations in excess of 350 mM, corresponding to about 10 7 times that found in seawater. Vanadium accumulated is reduced to the +3 oxidation state via the +4 oxidation state and stored in vacuoles of vanadocytes (vanadium-containing blood cells) where high levels of protons and sulfate are also contained. To investigate this unusual phenomenon, we isolated several proteins and genes that are expressed in vanadocytes. To date, three types of vanadium-binding protein, designated as Vanabins, have been isolated, with molecular masses of 12.5, 15, and 16 kDa, along with the cDNAs encoding these proteins. In addition, four types of enzyme related to the pentose phosphate pathway that produces NADPH were revealed to be located in vanadocytes. The pentose phosphate pathway participates in the reduction of V(V) to V(IV). The cDNA for each of the vacuolar-type H +ATPase (VATPase) A, B, C, and D subunits, which are located on the vacuolar membranes of vanadocytes, has been isolated and analyzed. VATPase generates a proton-motive force, and is thought to provide the energy for vanadium accumulation. To clarify the entire mechanism involved in the accumulation and reduction, much more genes and proteins expressed in the blood cells need to be systematically identified. Thus, we have performed an expressed sequence tag (EST) analysis of blood cells and have established the functional assay system to elucidate the functions of genes and proteins obtained from ascidian blood cells.

Expressed sequence tag analysis of blood cells in the vanadium-rich ascidian, Ascidia sydneiensis samea--a survey of genes for metal accumulation.

Some species in the family Ascidiidae accumulate vanadium at concentrations in excess of 350 mM, which corresponds to about 10(7) times that found in seawater. The vanadium ions are stored in vacuoles located within vanadium-containing blood cells, vanadocytes. To investigate the phenomenon, an expressed sequence tag analysis (EST) of a cDNA library of Ascidia sydneiensis samea blood cells was carried out. Three hundred clones were obtained and sequenced by EST analysis. A similarity search revealed that 158 of the clones (52.7%) were known genes, and 142 of the clones (47.3%) did not have any similarity to genes registered in the SwissProt database. According to the functions of their genes the identified EST clones were categorized into eight types of clones; these consisted of genes; metal-related proteins (29 clones), signal transduction (22 clones), protein synthesis (17 clones), nuclear proteins (17 clones), cytoskeleton and motility (14 clones), energy conversion (3 clones), hypothetical proteins (11 clones), and others (45 clones). The ferritin homologue has a high degree of similarity to that of mammals; the iron-binding sites of ferritin are well conserved including His-118 which is important for capturing Fe(2+), also works as a ligand for VO(2+).

Immunological detection of a vacuolar-type H(+)-ATPase in vanadocytes of the ascidian Ascidia sydneiensis samea.

Ascidians belonging to the family Ascidiidae are known to accumulate vanadium from seawater in their blood cells, concentrating vanadium by a factor of 10(7). Among several different types of blood cell, the signet ring cells have both high levels of vanadium and a low pH. These observations suggest the possibility that proton ions concentrated by a H(+)-ATPase are energetically linked to the accumulation of vanadium. In the present experiments, therefore, we made an immunological search for a H(+)-ATPase in the vacuolar membranes of the signet ring cells, as a first step in our attempts to clarify the energetics of the accumulation of vanadium by these cells. Antibodies raised against the 72-kDa and 57-kDa subunits of a vacuolar-type H(+)-ATPase from bovine chromaffin granules reacted with the vacuolar membranes of signet ring cells. Immunoblotting analysis confirmed that specific antigens in ascidian blood cells actually reacted with the antibodies. Furthermore, addition of bafilomycin A1, a specific inhibitor of vacuolar-type H(+)-ATPase, inhibited the uptake of protons by the vacuoles of signet ring cells. Thus, the addition of bafilomycin A1 inhibited the pumping function of the vacuoles of signet ring cells, with resultant neutralization of the contents of the vacuoles.

Extraction of a Vanadium-Binding Substance (Vanadobin) from the Blood Cells of Several Ascidian Species.

A combination of techniques, including chromatography on Sephadex G-15 and SE-cellulose columns and neutron activation analysis for vanadium determination, was used to extract (at low pH) a vanadium-binding substance (vanadobin) from the blood cells of the ascidian species: Ascidia ahodori OKA, A. gemmata SLUITER, A. zara OKA, Corella japonica HERDMAN, and Ciona intestinalis (LINNE). In general, ascidians can be classified into two different categories based on vanadium content: species of the family Ascidiidae contain high levels of vanadium, whereas those in the Cionidae and Corellidae do not always have such high amounts. Because Ciona intestinalis and Corella japonica do have vanadobin in their blood cells, vanadobin may well be a universal complex in ascidians, having the role of accumulating vanadium in blood cells and maintaining its concentration. The blood cells of A. gemmata contained the highest amount of vanadium. Vanadobin extracted from these cells exhibits absorption spectra, not only in the ultraviolet region, but also in the visible region; such spectra correspond to those observed in vanadium complexes in oxidation states of +3 and +4.

Studies of the Blood and Tests of Some Australian Ascidians. I. The Blood of Pyura stolonifera (Heller)

The blood cells of Pyura stolonifera are described and figured. Descriptions are given of the formation of the various cell types from the primitive lymphocytes of the blood. The presence of morula-shaped cells, which appear to correspond structurally with the vanadium-containing cells of members of the family Ascidiidae, is noted and the reaction of these cells to certain histological and histochemical reagents described. Vanadium cannot be detected spectrographically in the ashed corpuscles but an iron compound with somewhat similar properties to the vanadium chromogen of the Ascidiidae is present. The iron is present in the ferrous condition and is capable of being liberated by acids. The iron compound has marked reducing properties and will reduce cytochrome c anaerobically. It is found in association with protein and an aminopolysaccharide. The importance of this association is discussed. Investigations on the intracorpuscular acidity of the morula-shaped corpuscles reveal that, although acid is present, the hydrogen ion concentration is not as great as in the vanadium-containing cells of the Ascidiidae. This can be correlated with the lower intracorpuscular sulphate concentration of the present species. Analyses of the inorganic composition of the plasma show that the sulphate concentration is slightly over half that of the external sea-water. The results of these and other investigations are compared with those obtained by workers using ascidians belonging to other families.